diff options
| -rw-r--r-- | arch/x86/include/asm/pgtable-2level.h | 17 | ||||
| -rw-r--r-- | arch/x86/include/asm/pgtable-3level.h | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/pgtable-invert.h | 32 | ||||
| -rw-r--r-- | arch/x86/include/asm/pgtable.h | 38 | ||||
| -rw-r--r-- | arch/x86/include/asm/pgtable_64.h | 2 |
5 files changed, 80 insertions, 11 deletions
diff --git a/arch/x86/include/asm/pgtable-2level.h b/arch/x86/include/asm/pgtable-2level.h index fd74a11959de..89c50332a71e 100644 --- a/arch/x86/include/asm/pgtable-2level.h +++ b/arch/x86/include/asm/pgtable-2level.h @@ -77,4 +77,21 @@ static inline unsigned long pte_bitop(unsigned long value, unsigned int rightshi #define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_low }) #define __swp_entry_to_pte(x) ((pte_t) { .pte = (x).val }) +/* No inverted PFNs on 2 level page tables */ + +static inline u64 protnone_mask(u64 val) +{ + return 0; +} + +static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask) +{ + return val; +} + +static inline bool __pte_needs_invert(u64 val) +{ + return false; +} + #endif /* _ASM_X86_PGTABLE_2LEVEL_H */ diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h index cdaa58c9b39e..0c89891c7b44 100644 --- a/arch/x86/include/asm/pgtable-3level.h +++ b/arch/x86/include/asm/pgtable-3level.h @@ -184,4 +184,6 @@ static inline pmd_t native_pmdp_get_and_clear(pmd_t *pmdp) #define __pte_to_swp_entry(pte) ((swp_entry_t){ (pte).pte_high }) #define __swp_entry_to_pte(x) ((pte_t){ { .pte_high = (x).val } }) +#include <asm/pgtable-invert.h> + #endif /* _ASM_X86_PGTABLE_3LEVEL_H */ diff --git a/arch/x86/include/asm/pgtable-invert.h b/arch/x86/include/asm/pgtable-invert.h new file mode 100644 index 000000000000..177564187fc0 --- /dev/null +++ b/arch/x86/include/asm/pgtable-invert.h @@ -0,0 +1,32 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_PGTABLE_INVERT_H +#define _ASM_PGTABLE_INVERT_H 1 + +#ifndef __ASSEMBLY__ + +static inline bool __pte_needs_invert(u64 val) +{ + return (val & (_PAGE_PRESENT|_PAGE_PROTNONE)) == _PAGE_PROTNONE; +} + +/* Get a mask to xor with the page table entry to get the correct pfn. */ +static inline u64 protnone_mask(u64 val) +{ + return __pte_needs_invert(val) ? ~0ull : 0; +} + +static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask) +{ + /* + * When a PTE transitions from NONE to !NONE or vice-versa + * invert the PFN part to stop speculation. + * pte_pfn undoes this when needed. + */ + if (__pte_needs_invert(oldval) != __pte_needs_invert(val)) + val = (val & ~mask) | (~val & mask); + return val; +} + +#endif /* __ASSEMBLY__ */ + +#endif diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 84c62d950023..2ed1556d99b1 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -148,19 +148,29 @@ static inline int pte_special(pte_t pte) return pte_flags(pte) & _PAGE_SPECIAL; } +/* Entries that were set to PROT_NONE are inverted */ + +static inline u64 protnone_mask(u64 val); + static inline unsigned long pte_pfn(pte_t pte) { - return (pte_val(pte) & PTE_PFN_MASK) >> PAGE_SHIFT; + unsigned long pfn = pte_val(pte); + pfn ^= protnone_mask(pfn); + return (pfn & PTE_PFN_MASK) >> PAGE_SHIFT; } static inline unsigned long pmd_pfn(pmd_t pmd) { - return (pmd_val(pmd) & pmd_pfn_mask(pmd)) >> PAGE_SHIFT; + unsigned long pfn = pmd_val(pmd); + pfn ^= protnone_mask(pfn); + return (pfn & pmd_pfn_mask(pmd)) >> PAGE_SHIFT; } static inline unsigned long pud_pfn(pud_t pud) { - return (pud_val(pud) & pud_pfn_mask(pud)) >> PAGE_SHIFT; + unsigned long pfn = pud_val(pud); + pfn ^= protnone_mask(pfn); + return (pfn & pud_pfn_mask(pud)) >> PAGE_SHIFT; } #define pte_page(pte) pfn_to_page(pte_pfn(pte)) @@ -359,19 +369,25 @@ static inline pgprotval_t massage_pgprot(pgprot_t pgprot) static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot) { - return __pte(((phys_addr_t)page_nr << PAGE_SHIFT) | - massage_pgprot(pgprot)); + phys_addr_t pfn = page_nr << PAGE_SHIFT; + pfn ^= protnone_mask(pgprot_val(pgprot)); + pfn &= PTE_PFN_MASK; + return __pte(pfn | massage_pgprot(pgprot)); } static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot) { - return __pmd(((phys_addr_t)page_nr << PAGE_SHIFT) | - massage_pgprot(pgprot)); + phys_addr_t pfn = page_nr << PAGE_SHIFT; + pfn ^= protnone_mask(pgprot_val(pgprot)); + pfn &= PHYSICAL_PMD_PAGE_MASK; + return __pmd(pfn | massage_pgprot(pgprot)); } +static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask); + static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) { - pteval_t val = pte_val(pte); + pteval_t val = pte_val(pte), oldval = val; /* * Chop off the NX bit (if present), and add the NX portion of @@ -379,17 +395,17 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) */ val &= _PAGE_CHG_MASK; val |= massage_pgprot(newprot) & ~_PAGE_CHG_MASK; - + val = flip_protnone_guard(oldval, val, PTE_PFN_MASK); return __pte(val); } static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) { - pmdval_t val = pmd_val(pmd); + pmdval_t val = pmd_val(pmd), oldval = val; val &= _HPAGE_CHG_MASK; val |= massage_pgprot(newprot) & ~_HPAGE_CHG_MASK; - + val = flip_protnone_guard(oldval, val, PHYSICAL_PMD_PAGE_MASK); return __pmd(val); } diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h index 67f2fe43a593..221a32ed1372 100644 --- a/arch/x86/include/asm/pgtable_64.h +++ b/arch/x86/include/asm/pgtable_64.h @@ -235,6 +235,8 @@ extern void cleanup_highmap(void); extern void init_extra_mapping_uc(unsigned long phys, unsigned long size); extern void init_extra_mapping_wb(unsigned long phys, unsigned long size); +#include <asm/pgtable-invert.h> + #endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_PGTABLE_64_H */ |